In the proposed work we plan to continue our studies on the action of glucocorticoids (primarily dexamethasone) on the structure and function of hepatic cellular organelles. The primary focus of the current work is to study the effects of hormones on the endoplasmic reticulum, particularly the smooth endoplasmic reticulum (SER). In these studies we will study by electron microscopy the hormonally-induced alterations in structure of the SER and we will sub-fractionate the ER into rough and smooth microsomes. In some work the membranes of the rough and smooth microsmes will be further purified by removing adsorbed and other proteins associated with the ER. Localization and alterations in enzyme content of the membranes will be studied. Particularly important for this work will be hormonally-induced changes in glucose-6-phosphatase. In addition, assays will be carried out for several enzymes involved in hepatic glycogen metabolism. Included in the enzymes to be studied are glycogen synthase, glycogen phosphorylase, synthase phosphatase, and phosphorylase phatase. We intend to determine if any of these enzymes show an association with membranes of the SER and if this association is modified by hormonal stimulation.